<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        h1 {
            color: rgb(255,0,0);
            /*反色*/
            color: rgb(0,255,255);
            color: rgb(0,255,0);
            color: rgb(255,0,255);
            color: rgb(0,0,255);
            color: rgb(255,255,0);
            color: rgb(0,0,0);
            color: rgb(255,255,255);
            color: rgb(128,128,128);
            color:rgb(127,127,127);


            color: #ff0000;
            color: #00ff00;
            color: #0000ff;
            /*简写*/
            color: #f00;
            color: #0f0;
            color: #00f;

            color: rgba(255,0,0,1);
            color: rgba(255,0,0,0.8);
            color: rgba(255,0,0,0.6);
            color: rgba(255,0,0,0.4);
            color: rgba(255,0,0,0.2);
            color: rgba(255,0,0,0);




        }

        .d1 {
            width: 500px;
            height: 300px;
            background-image: linear-gradient(30deg,red,cyan);
        }


        .d2
        {
            width: 50px;
            height: 100px;
            background-image: url("img/mr.png");
            background-color: cyan;
            background-size: 50px 100px;

        }

        .d3
        {
            width: 300px;
            height: 500px;
            background-image: url("img/mr.png");
            border: 5px solid red;
            background-repeat: no-repeat;
            background-position: 0 0;
            background-position: 50px 0;
            background-position: 0 50px;
            background-position: -50px -50px;
            background-position: left top;
            background-position: right bottom;
            background-position: center;
            background-position: 50% 50%;


        }

    </style>
</head>
<body>
    <h1>测试颜色</h1>
    <div class="d1"></div>
    <div class="d2"></div>
    <div class="d3"></div>
</body>
</html>